You are here
Search results
(1 - 20 of 86,397)
Pages
- Title
- Molecular epidemiology, pangenomic diversity, and comparative genomics of Campylobacter jejuni
- Creator
- Rodrigues, Jose Alexandre
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
-
Campylobacter jejuni, the leading cause of bacterial gastroenteritis in the United States, is often resistant to commonly used antibiotics and has been classified as a serious threat to public health. Through this work, we sought to evaluate infection trends, quantify resistance frequencies, identify epidemiological factors associated with infection, and use whole-genome sequencing (WGS) as well as comparative phylogenomic and pangenomic approaches to understand circulating C. jejuni...
Show moreCampylobacter jejuni, the leading cause of bacterial gastroenteritis in the United States, is often resistant to commonly used antibiotics and has been classified as a serious threat to public health. Through this work, we sought to evaluate infection trends, quantify resistance frequencies, identify epidemiological factors associated with infection, and use whole-genome sequencing (WGS) as well as comparative phylogenomic and pangenomic approaches to understand circulating C. jejuni populations in Michigan. C. jejuni isolates (n=214) were collected from patients via an active surveillance system at four metropolitan hospitals in Michigan between 2011 and 2014. Among the 214 C. jejuni isolates, 135 (63.1%) were resistant to at least one antibiotic. Resistance was observed for all nine antibiotics tested yielding 11 distinct resistance phenotypes. Tetracycline resistance predominated (n=120; 56.1%) followed by resistance to ciprofloxacin (n= 49; 22.9%), which increased from 15.6% in 2011 to 25.0% in 2014. Notably, patients with ciprofloxacin resistant infections were more likely to report traveling in the past month (Odds Ratio (OR): 3.0; 95% confidence interval (CI): 1.37, 6.68) and international travel (OR: 9.8; 95% CI: 3.69, 26.09). To further characterize these strains, we used WGS to examine the pangenome and investigate the genomic epidemiology of this set of C. jejuni strains recovered from Michigan patients. Among the 214 strains evaluated, 83 unique multilocus sequence types (STs) were identified that were classified as belonging to 19 previously defined clonal complexes (CCs). Core-gene phylogenetic reconstruction based on 615 genes identified three clades, with Clade I comprising six subclades (IA-IF) and predominating (83.2%) among the strains. Because specific cattle-associated STs, such as ST-982, predominated among strains from Michigan patients, we also examined a collection of 72 C. jejuni strains from cattle recovered during an overlapping time period by WGS. Several phylogenetic analyses demonstrated that most cattle strains clustered separately within the phylogeny, but a subset clustered together with human strains. Hence, we used high quality single nucleotide polymorphism (hqSNP) profiling to more comprehensively examine those cattle and human strains that clustered together to evaluate the likelihood of interspecies transmission. Notably, this method distinguished highly related strains and identified clusters comprising strains from both humans and cattle. For instance, 88 SNPs separated a cattle and human strain that were previously classified as ST-8, while the human and cattle derived ST-982 strains differed by >200 SNP differences. These findings demonstrate that highly similar strains were circulating among Michigan patients and cattle during the same time period and highlight the potential for interspecies transmission and diversification within each host. In all, the data presented illustrate that WGS and pangenomic analyses are important tools for enhancing our understanding of the distribution, dissemination, and evolution of specific pathogen populations. Combined with more traditional phenotypic and genotypic approaches, these tools can guide the development of public health prevention and mitigation strategies for C. jejuni and other foodborne pathogens.
Show less
- Title
- I. Determination of Absolute Configuration of Chiral 1,2-Diols. II. Progress Towards the Total Synthesis of Napyradiomycin A1.
- Creator
- Torabi Kohlbouni, Saeedeh
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
-
This dissertation focuses on two parts. The first part introduces an operationally simple and microscale method for the absolute stereochemical determination of 1,2-diols. In situ derivatization of 1,2-diols with dinaphthyl borinic acid generates the induced helicity of the two naphthyl groups, which leads to an observable ECCD spectrum. The observed P or M helicity follows a predictable trend for S and R chiral 1,2-diols, respectively.The Second chapter is the progress towards the asymmetric...
Show moreThis dissertation focuses on two parts. The first part introduces an operationally simple and microscale method for the absolute stereochemical determination of 1,2-diols. In situ derivatization of 1,2-diols with dinaphthyl borinic acid generates the induced helicity of the two naphthyl groups, which leads to an observable ECCD spectrum. The observed P or M helicity follows a predictable trend for S and R chiral 1,2-diols, respectively.The Second chapter is the progress towards the asymmetric catalytic synthesis of napyardiomycin A1. The chapter is divided to three sections. The first section is installation of chlorine chiral center at C3. This goal is achieved using cinchona chiral catalyst, and DCDMH as chloronium source. The second section is the synthesis of the -lapachone core of napyradiomycin A1, was accomplished using Diels-Alder/aromatization cascade reaction. The last section shows our effort toward the attachment of geranyl side chain.
Show less
- Title
- DEVELOPING LIGNIN-BASED EPOXY AND POLYURETHANE RESINS
- Creator
- Nikafshar, Saeid
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
-
Lignin, the most abundant natural aromatic polymer, is currently produced as by-product during biorefinery and chemical pulping processes. Lignin is rich in hydroxyl functional groups (both phenolic and aliphatic OH), making it an excellent raw material for synthesizing epoxy and polyurethane resins. However, there are several challenges in utilizing unmodified lignins as feedstock for product development, including high polydispersity/heterogeneity, low reactivity, poor accessibility of...
Show moreLignin, the most abundant natural aromatic polymer, is currently produced as by-product during biorefinery and chemical pulping processes. Lignin is rich in hydroxyl functional groups (both phenolic and aliphatic OH), making it an excellent raw material for synthesizing epoxy and polyurethane resins. However, there are several challenges in utilizing unmodified lignins as feedstock for product development, including high polydispersity/heterogeneity, low reactivity, poor accessibility of hydroxyl groups for reaction with co-monomers low solubility in common organic solvents, and dark color. There are significant variations in lignin characteristics, depending on the source of biomass and isolation methods. Therefore, in-depth lignin characterization is needed to provide the basic knowledge of the structural, chemical, and thermal properties to facilitate lignin valorization.This study was focused on lignin characterization and development of lignin-based epoxy and polyurethane resins. First, a wide range of lignin samples was fully characterized by measuring their ash contents, elemental analyses, hydroxyl contents, chemical structures, molar mass distributions, and thermal properties. Next, a novel method was developed to measure the reactivity of thirteen different unmodified lignins toward biobased epichlorohydrin (ECH). A partial least square regression (PLS-R) model (with 92 % fitting accuracy and 90 % prediction ability) was created to study the correlation between lignin properties and epoxy content. The results showed that lignins with higher phenolic hydroxyl contents and lower molecular weights were more suitable for replacing 100 % of toxic bisphenol A (BPA) in the formulation of resin precursors. Additionally, two epoxidized lignin samples (with the highest epoxy contents) were cured using a biobased hardener (Cardolite from cashew nutshell), showed comparable thermomechanical performances and thermal stabilities to a petroleum-based epoxy system. Biobased waterborne polyurethane resins (PUDs) were also developed by entirely replacing the petroleum-based polyol and the internal emulsifier with either alkaline pre-extraction lignins or enzymatic hydrolysis lignins as well as tartaric acid (a biobased diacid). The formulated resins had zero VOC (volatile organic compound), which was achieved by replacing toxic n-methyl-2-pyrrolidone (NMP) with cyrene (a biobased solvent). To further improve the mechanical properties of our biobased PUD resins, 20 wt.% of lignin was substituted with low hydroxyl value soy-polyol, which increased their tensile strength and elongation at break to 87% and 68% of a commercial PUD resin. The results of this study demonstrated that it is imperative to fully characterize lignin and choose the right lignin for each specific application. This approach enabled us to entirely replace petroleum-based raw materials (BPA and polyol) with lignin and formulate biobased epoxy and polyurethane resins.
Show less
- Title
- Development and application of hierarchical models for monitoring avian soundscapes, populations, and communities
- Creator
- Doser, Jeffrey W.
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
-
Climate change, land use change, and other anthropogenic pressures are increasing species extinctions, phenology shifts, and drastic population declines. Avian populations and communities are particularly vulnerable to global change given their mobile and migratory life history strategies. Avian abundance has drastically declined throughout North America over several decades, which is compounded by phenological shifts in breeding periods and migratory patterns. Informed management and...
Show moreClimate change, land use change, and other anthropogenic pressures are increasing species extinctions, phenology shifts, and drastic population declines. Avian populations and communities are particularly vulnerable to global change given their mobile and migratory life history strategies. Avian abundance has drastically declined throughout North America over several decades, which is compounded by phenological shifts in breeding periods and migratory patterns. Informed management and conservation of avian populations and communities requires large-scale monitoring programs, as well as associated inferential tools to provide statistically robust inference using multiple data sources. In this dissertation, I develop a suite of hierarchical modeling approaches to understand avian soundscapes, populations, and communities. I leverage a hierarchical Bayesian modeling framework, which is ideally suited for complex wildlife data with numerous types of observation error and dependencies among data points. In Chapter 1, I provide a brief overview of avian monitoring approaches and their associated statistical analysis frameworks. In Chapters 2 and 3, I develop hierarchical models for the analysis of complex avian soundscape data, and apply these approaches to two case studies. In Chapter 2, I apply a two-stage hierarchical beta regression model to quantify the relationship between anthropogenic and biological sounds in avian soundscapes in western New York. In Chapter 3, I use a multivariate linear mixed model to assess disturbance impacts of a shelterwood logging on avian soundscapes in northern Michigan. In Chapter 4, I develop a multi-region, multi-species abundance model to quantify trends of avian species and communities using point count data across a network of National Parks in the northeastern US. In Chapters 5 and 6, I use a model-based data integration approach to yield improved inference on avian population and communities. In Chapter 5, I integrate automated acoustic recording data with point count data to estimate avian abundance, which I apply to a case study on the Eastern Wood Pewee (Contopus virens) in a National Historical Park in Vermont. In Chapter 6, I develop an integrated community occupancy model that combines multiple types of detection-nondetection data for inference on species-specific and community level occurrence dynamics, which I use to assess occurrence dynamics of a foliage-gleaning bird community in New Hampshire. These results exhibit the value of hierarchical models to partition ecological data into distinct observation and ecological components for improved inference on avian population and community dynamics. Future work should continue to leverage complex data sources within hierarchical modeling frameworks to address pressing conservation and management questions on avian populations, communities, and the ecosystem services they provide.
Show less
- Title
- Intraoperative blood glucose management : a quality improvement project
- Creator
- Baker, Jake (Nurse)
- Date
- 2022
- Collection
- Doctor of Nursing Practice Projects
- Description
-
Perioperative hyperglycemia is associated with a myriad of post-surgical complications including an increased incidence of surgical site infections and prolonged hospital stays. The use of an evidence-based perioperative blood glucose management protocol reduces morbidity and mortality in adult patients undergoing surgical procedures. The project team describes a cost-effective quality improvement initiative aimed at improving protocol adherence by integrating an easy-to-use protocol...
Show morePerioperative hyperglycemia is associated with a myriad of post-surgical complications including an increased incidence of surgical site infections and prolonged hospital stays. The use of an evidence-based perioperative blood glucose management protocol reduces morbidity and mortality in adult patients undergoing surgical procedures. The project team describes a cost-effective quality improvement initiative aimed at improving protocol adherence by integrating an easy-to-use protocol algorithm, order sets, and practice reminders into an existing electronic health record system.
Show less
- Title
- Improving perioperative nausea and vomiting prophylaxis protocol compliance
- Creator
- Franz, Allison
- Date
- 2022
- Collection
- Doctor of Nursing Practice Projects
- Description
-
Postoperative nausea and vomiting (PONV) is a significant concern in anesthesia practice. Evidence-based guidelines have sought to provide recommendations on identifying patients at risk for PONV and mitigating its effect with multimodal antiemetic strategies. An anesthesia department within a large teaching hospital uses the Anesthesiology Performance Improvement and Report Exchange guidelines to identify and manage patients at risk for PONV. These guidelines are intended to integrate best...
Show morePostoperative nausea and vomiting (PONV) is a significant concern in anesthesia practice. Evidence-based guidelines have sought to provide recommendations on identifying patients at risk for PONV and mitigating its effect with multimodal antiemetic strategies. An anesthesia department within a large teaching hospital uses the Anesthesiology Performance Improvement and Report Exchange guidelines to identify and manage patients at risk for PONV. These guidelines are intended to integrate best practices into anesthetic care and improve overall surgical outcomes. The anesthesia department currently has a PONV protocol in place that aligns with the guidelines but has not achieved their compliance benchmark. This evidence-based quality improvement project describes interventions proposed to increase compliance with the PONV protocol. To address poor PONV compliance, an anonymous survey was developed to assess anesthesia provider's current familiarity with the new PONV guidelines and identify misconceptions. A visual feedback system was implemented using a preliminary confidential list that anonymizes staff. This allowed individual providers to identify their own performance in relation to their peers in a non-punitive way. The results of this quality improvement project demonstrate that the proposed interventions increased departmental compliance.
Show less
- Title
- Development and implementation of an enhanced recovery after surgery protocol for women undergoing a mastectomy
- Creator
- Braun, Michael
- Date
- 2022
- Collection
- Doctor of Nursing Practice Projects
- Description
-
This evidenced-based practice initiative includes the development and implementation of an evidence-based enhanced recovery after surgery (ERAS) guideline with a specific focus on the incidence of postoperative nausea and vomiting (PONV) and opioid administration in the postoperative setting. The clinical question was in adult women, age 18 years or greater, undergoing a mastectomy procedure, does the implementation of an ERAS guideline lower the incidence of PONV and reduce morphine...
Show moreThis evidenced-based practice initiative includes the development and implementation of an evidence-based enhanced recovery after surgery (ERAS) guideline with a specific focus on the incidence of postoperative nausea and vomiting (PONV) and opioid administration in the postoperative setting. The clinical question was in adult women, age 18 years or greater, undergoing a mastectomy procedure, does the implementation of an ERAS guideline lower the incidence of PONV and reduce morphine milligram equivalent (MME) requirements in a post-anesthesia care unit (PACU)? Patients undergoing breast cancer surgery have multiple risk factors and the reported incidence of PONV reaches up to 80%. Over half of post-surgical breast cancer patients develop neuropathic pain syndromes. A mastectomy ERAS guideline was developed then applied to the perioperative course of 22 patients. It was found that following an ERAS guideline reduced the incidence of PONV by 17% and reduced the average MME by 13.5 equivalents. Project implications include potential cost savings, reduced PACU length of stay, and improved patient outcomes.
Show less
- Title
- Michigan potato research report. Vol. 53 (2021)
- Date
- 2022
- Collection
- Michigan Potato Research Reports
- Title
- The Greenerside. Vol. 59 (2021 Fall)
- Date
- 2021-09/2021-11
- Collection
- The Greenerside
- Title
- Australian Turfgrass Management Journal. Vol. 23 no. 5 (2021 September/October)
- Date
- 2021-09
- Collection
- Australian Turfgrass Management Journal
- Title
- The Newsletter of the Golf Course Superintendents Association of New England, Inc. (2021 September/October)
- Date
- 2021-09
- Collection
- The Newsletter of the Golf Course Superintendents Association of New England, Inc.
- Title
- Tee to Green. Vol. 52 no. 3 (2021 August/September)
- Date
- 2021-08
- Collection
- Tee to Green
- Title
- Course Conditions. No. 52 (2021 Q3)
- Date
- 2021-07/2021-09
- Collection
- Course Conditions
- Title
- Australian Turfgrass Management Journal. Vol. 23 no. 4 (2021 July/August)
- Date
- 2021-07
- Collection
- Australian Turfgrass Management Journal
- Title
- The Newsletter of the Golf Course Superintendents Association of New England, Inc. (2021 July/August)
- Date
- 2021-07
- Collection
- The Newsletter of the Golf Course Superintendents Association of New England, Inc.
- Title
- The Greenerside. Vol. 58 (2021 Summer)
- Date
- 2021-06/2021-08
- Collection
- The Greenerside
- Title
- Australian Turfgrass Management Journal. Vol. 23 no. 3 (2021 May/June)
- Date
- 2021-05
- Collection
- Australian Turfgrass Management Journal
- Title
- The Newsletter of the Golf Course Superintendents Association of New England, Inc. (2021 May/June)
- Date
- 2021-05
- Collection
- The Newsletter of the Golf Course Superintendents Association of New England, Inc.
- Title
- Tee to Green. Vol. 52 no. 1 (2021 April)
- Date
- 2021-04
- Collection
- Tee to Green
- Title
- The Greenerside. Vol. 57 (2021 Spring)
- Date
- 2021-03/2021-05
- Collection
- The Greenerside